1. Field of the Invention
This invention relates to disk drive suspensions, and, more particularly, to wireless disk drive suspensions in which the electrical conductor comprises a flexible circuit laminate of trace conductors, an insulative plastic film, and a support such as a stainless steel layer. The invention further relates to an improved method for the assembly of such suspensions including improvements in lowering of capital equipment costs, in speed and accuracy of positioning and in the maintenance of the accurate position before and during welding. In the invention, the alignment of the parts is with reference to themselves, and does not depend on the accuracy of a machine vision apparatus. The invention particularly concerns the use of cooperating mechanical locators areally distributed on the load beam and the flexible circuit and extending through the common plane between them to enable the rapid, correct placement of the flexible circuit on the load beam.
2. Related Art
Disk drive suspensions are quite small and the attachment thereto of the wireless electrical conductor is problematical. The components are spot-welded but must be first aligned with as perfect a registration as possible. Machine vision relies on markers to read the position of the load beam in a welding fixture and through X, Y movements places the wireless laminate as desired. This is a slow process and only as accurate as the machine precision in reading of the markers will allow. In addition, the accompanying fixturing is typically quite costly, and, since many suspension runs are small, there is a relatively large capital charge on every part made in these runs. Further, present systems are deficient in maintaining the desired alignment, once achieved, until welding is effected. Relative movement of the parts will detract from the accuracy of the result although the alignment was perfect.
It is an object of the invention, therefore, to provide a method for the assembly of disk drive suspension components. It is a further object to achieve their proper alignment without use of machine vision. It is a further object to maintain the aligned parts free of relative movement until welded or otherwise fixed together. Yet another object is to have the parts physically modified such that they will self-align solely by reference to themselves. It is a further object to provide a disk drive suspension comprising load beam and flexible circuit components having the noted features.
These and other objects to become apparent hereinafter are realized in the invention method of assembling in a predetermined alignment the load beam and flexible circuit components of a disk drive suspension having proximate and distal ends that includes juxtaposing at a common contact plane a suspension load beam having a longitudinal axis and a flexible circuit having a longitudinal axis, the flexible circuit comprising a laminate of trace conductors, an insulative film and a metal support layer engaging the load beam in the contact plane, intersecting longitudinally spaced first and second locator structures on the load beam with longitudinally spaced third and fourth locator structures on the flexible circuit across the common contact plane to locate the load beam and flexible circuit in the predetermined alignment, and thereafter fixing the load beam and flexible circuit together in the predetermined alignment
In this and like embodiments, typically, the method further includes extending the first and second locator structures through the common plane, and receiving the first and second locator structures with the third and fourth locator structures respectively, welding the flexible circuit metal layer to the load beam in locations spaced from the locator structures, locating the first and second locator structures at the suspension distal end, locating the third and fourth locator structures at the suspension proximate end, also forming in the load beam longitudinally spaced and axially aligned raised sections raised out of the general plane of the load beam, orienting the raised load beam sections normal to the longitudinal axis of the load beam, forming raised section receiving recesses in the flexible circuit metal layer to form the second and fourth locator structures, and also selecting a stainless steel metal layer, and intersecting fifth and sixth locator structures on the load beam and flexible circuit respectively across the common contact plane simultaneously with intersecting of the first through fourth locator structures, the fifth and sixth locator structures being laterally offset from the longitudinal axes of the load beam and flexible circuit.
In a further embodiment, the invention assembly method also includes extending the first through sixth locator structures through the common plane, and receiving the first, second and fifth locator structures with the third, fourth and sixth locator structures respectively.
In this and like embodiments, typically, there is further included welding the flexible circuit metal layer to the load beam in locations spaced from the locator structures, locating the first and third locator structure at the suspension distal end, locating the second, fourth and fifth and sixth locator structures at the suspension proximate end, forming in the load beam longitudinally spaced and axially aligned raised sections raised out of the general plane of the load beam as the first, second and fifth locator structures, orienting the raised load beam sections of the first and third locator structures normal to the longitudinal axis of the load beam, and orienting the fifth locator structure parallel to the longitudinal axis, and forming raised section receiving recesses in the metal layer to form the second, fourth and sixth locator structures, the recesses extending through the metal layer, the fifth and sixth locators being paired and located between the first and second paired locators and the third and fourth paired locators.
The invention further provides a disk drive suspension having proximate and distal ends and comprising a load beam and a flexible circuit laminate of trace conductors, an insulative film and a metal layer, the load beam and flexible circuit being fixed together on either side of a common plane, plural pairs of interfitting locator structures including a distal pair of first and second locator structures, a first proximate pair of third and fourth locator structures, and a second proximate pair of fifth and sixth locator structures, the first and second pairs being located on the longitudinal axes of the load beam and flexible circuit, the third pair being located laterally offset from longitudinal axes and between the first and second pairs at the proximate end of the suspension, the pair members being interfitting in common plane intersecting relation.
In this and like embodiments, typically, the first, second and third pairs of locator structures each comprise a raised metal section and a recessed metal section opposed across the common plane, the raised metal sections are each formed in the load beam as a load beam section raised out of the general plane of the load beam, the recessed metal sections are each formed of the metal layer, the raised metal sections are each formed in the load beam as a load beam section spaced from the general plane of the load beam, and the recessed metal sections include a recess extending through the metal layer.